JP2570402B2 - Optical information recording medium molding device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an optical information recording medium molding apparatus in which minute pits are formed on the surface of a plastic substrate.

(Prior Art) In recent years, optical information recording media such as digital audio discs and CDs have been widely used.

These optical information recording media and their molding devices will be described by taking a digital audio disk as an example.

FIG. 4 is a configuration diagram showing a row of a conventional digital audio disc, wherein FIG. 4A is a perspective view and FIG.
FIG. 2 is an enlarged perspective view of a main part, and FIG. 2C is an enlarged sectional view of a main part.

In the figure, a digital audio disk 9 has concentric pits 10 that are concave portions or convex portions corresponding to audio and video information signals formed on a surface of a substrate 9a made of a transparent plastic disc, for example, a polycarbonate resin. Thereafter, a reflective aluminum vapor-deposited layer 9b is formed on this surface, and a plastic protective film 9c is further formed.
The information signal is reproduced by reading the row of the pits 10 from the substrate 9a side with a laser beam 11 of a laser reading device (not shown).

A conventional example of a manufacturing apparatus in which a row of the pits 10 (recesses in this example) is formed on the substrate 9a has a disc-shaped space having the same shape as the substrate 9a, and has a convex shape corresponding to the row of the pits 10. A matrix, which is a plastic molding die having a row of pits for transfer, which is a portion or a concave portion (a convex portion in this example), is attached to a plastic molding machine such as an injection molding machine, and the polycarbonate melted in the cavity of the matrix. Plastic molding is performed by injecting plastic such as resin.

(Problems to be Solved by the Invention) In the example of the plastic molding apparatus for the substrate 9a in the conventional digital audio disc manufacturing apparatus as described above, the volume of the pit 10 is smaller than the volume of the substrate 9a which is a molded product. Very small volume (see dimensions in Fig. 4)
Therefore, a large plastic molding machine and energy are required. In addition, since this large molding machine requires high precision, there is a problem in the quality of the molded product.

Since the disk-shaped substrate 9a is a rigid body, the inherent characteristics of plastic and the accuracy of the pit 10, such as the warpage of the substrate 9a and the molding accuracy and quality of the pit 10, as well as the warping and the melting temperature of the plastic material used. There are many trade-offs between quality and quality, and many proposals have been made to solve these, but no definitive solution has been provided for this accuracy and quality.

In addition, it is considered that it is necessary to increase the density per volume of the optical information recording medium in response to the increase in the density of the optical information recording medium in the future. For example, a flexible optical information recording medium having a thickness of about 0.1 mm is required. When plastic molding is to be performed, the problems of accuracy and quality in the conventional plastic molding apparatus are even greater.

The present invention has been made in view of the above points, and is an optical information recording medium that is a relatively simple and low-cost apparatus, and that can manufacture a high-precision, high-quality optical information recording medium. It is an object to provide a molding device.

(Means for Solving the Problems) The optical information recording medium molding apparatus of the present invention is an optical information recording medium by using a matrix in which a transfer pit row of a convex portion or a concave portion according to an information signal is formed. In an optical information recording medium molding apparatus for transferring a pit row of concave portions or convex portions opposite to the transfer pits to a plastic substrate material, a sheet or plate-like plastic substrate material of a material substantially impermeable to ultraviolet light is supplied. A matrix formed of a material that transmits substantially ultraviolet light, pressing means for closely contacting and pressing the surface of the plastic substrate material to the surface of the matrix on which the transfer pit rows are formed, and It is configured to have ultraviolet irradiation means arranged on the back.

(Embodiment) The optical information recording medium molding apparatus of the present invention utilizes a novel plastic molding apparatus utilizing the phenomenon of light absorption and heat generation due to ultraviolet rays, from the viewpoint that only heat is required for plastic molding. .

At present, there is an ultraviolet curable resin that utilizes ultraviolet rays, which utilizes a chemical reaction due to ultraviolet rays, and is a method different from the method utilizing the heat generation phenomenon of the present invention. The ultraviolet light utilization method of the present invention focuses on the fact that almost all of the current engineering plastics have aromatics in the molecular structure, and thus the aromatic light of this material has a large light absorbency in the ultraviolet wavelength region. It was done.

In general, the heat generation effect of light increases the energy of a photon unit as the wavelength of the light becomes shorter, so that the energy of light is greater in visible light than in infrared light, and more in ultraviolet light than in infrared light. If the wavelength is further reduced, the energy of light is further increased. However, if the wavelength is 190 nm or less, there is a light absorption band due to oxygen in the air, so that it becomes difficult to use a wavelength shorter than this. Therefore, when so-called ultraviolet light having a wavelength of 200 to 300 nm is used, the light energy is large, which is effective for the apparatus of the present invention.

FIG. 3 is a configuration diagram for explaining the principle of the optical information recording medium molding apparatus of the present invention.

In the following description, as in the conventional example, an example of a molding apparatus for a digital audio disc in which the pits 10 formed on the disc-shaped transparent plastic substrate are concave portions will be described.

In the figure, reference numeral 1 denotes a matrix made of a material that transmits ultraviolet light, for example, a quartz glass, and a row of transfer pits 1a, which are convex portions corresponding to the row of the pits 10, is formed on the upper surface thereof. Since it is advantageous for the material of the matrix to have low adhesiveness to the plastic to be molded, for example, quartz glass, polyethylene or the like is effective. Reference numeral 2 denotes an ultraviolet lamp, which is disposed below the matrix 1 and irradiates the back surface of the matrix 1. 8a is the digital audio disk 9
Is a disk-shaped transparent plastic substrate material,
Since the material is required to absorb ultraviolet rays, those having an aromatic structure in the molecular structure are suitable, and
It is suitable that the plastic has a sudden decrease in Young's modulus when the plastic exceeds its softening point due to absorption of ultraviolet rays.
Suitable materials for this condition include, for example, polycarbonate, polyetherimide resin and the like, and polymethyl methacrylate, polyethylene terephthalate resin and the like are not suitable.

FIG. 2 is a graph showing the ultraviolet transmission characteristics of various plastics, in which the vertical axis represents light transmittance, the horizontal axis represents light wavelength, is polyetherimide, is polyethylene terephthalate,
Is a curve of polycarbonate, polymethyl methacrylate, polyethylene, and quartz glass.

Next, a molding cycle, which is an operation of the molding apparatus of the present invention, will be described with reference to FIGS.

The substrate material 8a is placed on the upper surface of the matrix 1, and the ultraviolet lamp 2 is irradiated.

Since the matrix 1 is made of quartz glass as described above, it hardly absorbs ultraviolet light as shown in FIG. 2, so that the light energy of the ultraviolet lamp 2 is hardly attenuated on the surface of the substrate material 8a. To reach. Since the substrate material 8a is made of polycarbonate or polyetherimide as described above, it is difficult for ultraviolet light to pass through as shown in FIG. 2, so that most of this light energy is absorbed by the surface of the substrate material 8a. Becomes high temperature and becomes a gelled state. In this case, since the thermal conductivity of the matrix 1 and the substrate material 8a are both very small as compared to metal, most of the heat generated on the surface of the substrate material 8a increases the temperature of this surface. Spent and convenient.

Then, the substrate material 8a whose surface is in a gel state
Is pressed against the surface of the matrix 1 by a device (not shown), whereby the inverted shape of the transfer pit 1a of the matrix 1 is transferred to the surface. In this case, this pressing force,
The molding conditions such as the pressing time, the output of the ultraviolet lamp 2 and the irradiation time are adjusted so that the row of the transfer pits 1a is completely transferred to the surface of the substrate material 8a. Next, when the irradiation of the ultraviolet lamp 2 is stopped, since the surrounding heat capacity is large, the surface of the substrate material 8a is rapidly cooled, and the molded product is easily peeled off.

Through the above steps, the substrate material 8a has the pits 10 which are concave portions formed by the transfer of the transfer pits 1a of the matrix 1 on the surface thereof, thereby forming the substrate 9a.

The substrate material 8a used here may be a flexible material having a thickness of about 0.1 mm or a rigid body having a thickness of about 1 to 2 mm,
Molding is possible by adjusting the molding conditions.

Further, the matrix 1 and the ultraviolet lamp 2 are used for the substrate material.
By arranging them on both sides of 8a, simultaneous molding of both sides of this substrate material 8a is also possible.

In the above description, an example of molding a digital audio disc has been described. However, the present invention is not limited to a disc-shaped disc but may be a card-shaped disc.

Next, an example of a molding apparatus for mass production based on the principle of the molding apparatus of the present invention will be described.

FIG. 1 is a configuration diagram illustrating an example of a molding apparatus for mass production in an optical information recording medium molding apparatus of the present invention.

In the figure, reference numeral 5 denotes a belt conveyor device. On the belt 5a of the device, a mass production substrate material 8 in which the substrate material 8a is continuously connected in a line is arranged in the longitudinal direction of the belt 5a. It is placed according to. A molding chamber 3 is provided above the belt conveyor device 5. In the molding chamber 3, the master block 1 and the mother block 1 are arranged such that the transfer pits 1 a face the mass-produced substrate material 8. An ultraviolet lamp 2 is disposed above the mold 1. The master mold 1 is pressed against the surface of the mass-produced substrate material 8 by the vertical device (not shown) in each molding cycle described above. In each molding cycle, a molding pad 6 provided below the mass-produced substrate material 8 transfers the mass-produced substrate material 8 via the belt 5a by an up-down device (not shown). Press Since the molding chamber 3 is evacuated by the vacuum pump 4 in each molding cycle, the substrate material 8 for mass production is brought into close contact with the matrix 1. Then, when the transfer pits 1a of the matrix 1 are transferred to the position of one digital audio disk of the mass production substrate material 8 by the above-described process, the mass production substrate material 8 is transferred to the belt conveyor device. By 5, the digital audio disk is fed by one digital audio disk in the longitudinal direction, and the next molding cycle is repeated.

The molding apparatus 7 for mass production having the above-described configuration has been described with respect to an example of taking one piece.
It goes without saying that a large number of units can be obtained by the above configuration.

 Next, embodiments of the present invention will be described.

[Example 1] A transfer pit of digital audio disc specification was formed on one surface by etching.
A quartz glass matrix having a diameter of 200 mm was placed on an ultraviolet lamp such that the transfer pits were facing upward. A well-dried 0.1 mm-thick polycarbonate sheet was closely adhered to the matrix. Then, the ultraviolet lamp was irradiated for each hour. The intensity of this ultraviolet lamp is 120 W / cm. After irradiation, the polycarbonate sheet was peeled off from the master mold, an aluminum layer was deposited on the surface to which the pits were transferred, and a 1 mm-thick, 120 mm-diameter compact disc specification plastic disk was bonded using an ultraviolet-curing resin, and then compacted. Cut to disk size. The compact disk was evaluated for reproduction by a reproducing machine, and the moldability of the pits was evaluated using an electron microscope. Table 1 shows the evaluation results. The meanings of the symbols in this table are as follows, and the same applies to Examples 2 and 3 described later.

Example 2 Instead of the quartz glass, a matrix having the transfer pits formed thereon by thermal transfer on a polyethylene film having a thickness of 1 mm was molded and evaluated in the same manner as in Example 1.
As for molding materials, polycarbonate and polyethylene terephthalate were compared. Table 2 shows the evaluation results.

[Example 3] Using a polycarbonate plate having a thickness of 1 mm as a molding material,
Molding and evaluation were performed in the same manner as in Example 1 above. In this case, it is conceivable that the adhesion between the matrix and the polycarbonate plate may be deteriorated. Therefore, a comparison was made between the case where degassing was performed between the matrix and the polycarbonate plate and the case where degassing was not performed. Deaeration is performed with a rotary pump, vacuum degree is 1mTo
rr. Table 3 shows the evaluation results.

(Effect of the Invention) The optical information recording medium molding apparatus of the present invention having the above configuration is a relatively simple and low-cost apparatus, and can manufacture a high-precision, high-quality optical information recording medium. Therefore, the cost of the optical information recording medium which is a molded product can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram for explaining an example of a molding apparatus for mass production in an optical information recording medium molding apparatus of the present invention, FIG. 2 is a graph showing ultraviolet transmission characteristics of various plastics, and FIG. 3 is optical information of the present invention. FIG. 4 is a configuration diagram illustrating the principle of a recording medium molding device, and FIG. 4 is a configuration diagram illustrating an example of a conventional digital audio disc. DESCRIPTION OF SYMBOLS 1 ... Matrix, 1a ... Transfer pit, 2 ... Ultraviolet lamp, 3 ... Molding chamber, 4 ... Vacuum pump, 5 ... Belt conveyor device, 5a ... Belt, 6 ... Molding pad, 8: substrate material for mass production, 8a: substrate material, 9: digital audio disc, 9a: substrate, 10: pit.

Claims (1)

(57) [Claims] 1. A plastic substrate material serving as an optical information recording medium is provided with a concave portion or a convex portion opposite to the transfer pit by a matrix having a transfer pit row of a convex portion or a concave portion corresponding to an information signal. In an optical information recording medium molding apparatus for transferring a pit row of a part, a sheet or a plate-like plastic substrate material of a material substantially impermeable to ultraviolet light is supplied, and a matrix formed of a material substantially transparent to ultraviolet light, A pressing means for bringing the surface of the plastic substrate material into close contact with the surface on which the transfer pit row of the matrix is formed, and an ultraviolet irradiation means arranged on the back of the matrix. Optical information recording medium molding device.